1. FIELD OF THE INVENTION
The present invention relates to the ultraviolet radiation curing of resin films and, more particularly, to a system for curing photosensitive resins on a tubular article with ultraviolet light.
2. DESCRIPTION OF THE PRIOR ART
Numerous systems have been devised for sterilizing containers used for foodstuffs, pharmacy items or the like. These systems commonly include a conveyor system operating in conjunction with one or more ultraviolet radiation sources and a reflector shield positioned to expose all surfaces to the concentrated ultraviolet source. Exemplary of such systems is an apparatus for sterilizing the interior of milk cartons described in U.S. Pat. No. 1,984,457. A system for sterilizing combs utilizing a central ultraviolet radiation source and an outer reflector shield is shown in U.S. Pat. No. 2,424,036.
With the discovery of photosensitive catalysts or modifiers usable with resinous materials, the ultraviolet radiation systems were modified to treat the light-sensitive resins for effecting a cure thereof. Ultraviolet light sources used for such resin curing devices commonly directed the ultraviolet radiation onto a narrow band of surface with the radiation concentrated into a limited area of application.
To effect the curing of large surface areas, banks of ultraviolet lamps were used within an enclosed chamber. The resin-coated materials were passed beneath the lamps for a specified period of time to effect the cure of the resin. Such an assembly is shown in U.S. Pat. No. 3,790,801.
Although still somewhat cumbersome, these systems were a substantial improvement over the previous heat curing systems commonly used for curing resinous materials. This is especially true for the resinous printing inks and coatings used on tubular articles. In such a system, large ovens and complicated conveyor systems were required for transporting the coated tubular articles through the ovens at a prescribed high temperature for a specified period of time. Such ovens require substantial amounts of fuel to operate and take up much space on an assembly line. Further, they require a large amount of maintenance to maintain in good working order.